Ant colonies > Internal structure of ants > Campaniform sensillae

Campaniform sensillae

The Campaniform Sensillae

These problematic organs have a very simple structure, consisting of a thin, bell- or umbrella-shaped piece of the chitinous cuticle forming the floor of a cavity in the much thicker, undifferentiated chitinous layer of the integument (Fig. 31, C-H)

This cavity is narrowed externally and usually, but not always, opens on the surface by means of a small pore ( E p ) . A very delicate nerve (n) terminates in the middle of the umbrella on its concave inner sur­face. Organs of this description are found in various parts of the insect body-in the borders of the mandibles, at the bases of the wing membranes, in the balancers of Diptera and in the trochanters and bases of the femora. They have been found in these joints of the legs and in the mandibles of ants by Janet (1904). In the mandibles occur also other organs which may represent modifications of the campani­form sensillae, although it seems more natural to refer them to the ampullaceous type. The function of the campani form sensillae is quite unknown.

Morphologically, according to Berlese, they may be derived from a simple protaesthesis, in which the glandular element is lacking and only the chitinogenous and nervous elements are present.